Engineering and Architecture
Nanoscience, Materials and Chemical Engineering
Light-driven transformation of carbon dioxide into fuels and chemicals
Carbon dioxide (CO2) accumulation in the atmosphere is undoubtedly caused by intense fossil fuel use by humankind. In addition, its negative effects on our environment should no longer be obviated, especially considering the worrisome event of global warming, which could compromise safe living conditions for most of humanity in the near future.
With an eye on this scenario, the capture and valorisation of CO2 by transforming it into useful products has a double potential: On one side, this approach may minimise the use on non-renewable fossil resources, and on the other, it may effectively prevent CO2 emissions. Overall, the recycling of CO2 is a perfect embodiment of circular carbon economy, albeit improvements in the efficiency of current CO2 transformation technologies are still urgently required.
The main motivation of this project is the utilisation and storage of sunlight via photo(electro)catalysis to transform carbon dioxide under mild conditions of temperature and pressure into versatile energetic chemicals (fuels) such as formic acid or methanol, able to be stored for a virtually unlimited time.
Carbon dioxide is an exceptionally stable molecule, and thus, its reduction into chemical species of commercial interest requires substantial energy supply. The action of sunlight as an energy source is crucial in the context of sustainable processes. However, light alone results in sluggish CO2 reduction in aqueous environments. Inspired in natural photosynthesis, which relies on impressively precise and sophisticated biomolecular mechanisms to channel the necessary energy and atom transfer processes, this project proposes to employ recyclable chemical species to assist as electron donors in the photo-reduction of CO2, and to explore favourable photocatalytic or photoelectrocatalytic systems for the production of carbon-based fuels such as formic acid or methanol.
Photoelectrocatalytic experiments will be designed and performed, aiming at enhancing CO2 reduction efficiency. Photoelectrodes (photocathodes) based on Earth-abundant elements, chiefly copper, zinc or iron, will be systematically prepared and tested. Once the best performing materials will be identified, photoelectrochemical cells for full-process CO2 reduction will be constructed using state-of-the-art anodes for the concomitant conversion of electron donors. Ultimately, in order to assess the possibility of wireless operation without the need for external electricity, photocatalytic experiments will be also carried out.
Regarding possible electron donors, their transformation into valuable coproducts will be sought. In this regard, the following classes of chemicals will be tested:
1. Halides, especially chloride, aiming at the production of chlorine or hypochlorite.
2. Inorganic or organic sulphides, which could result in production of elemental sulphur or polysulfides.
3. Biomass-derived oxygenates, among which alcohols and aldehydes may serve as models for artificial CO2 fixation towards more chemically complex structures.
Critical evaluation will be finally performed by estimating the productivity of the designed photoelectrochemical cells for fuel production under real-life, ideally natural sunlight, conditions. Sensitive parameters such as solar-to-fuel energy efficiency, or production costs, may be estimated as indicators for technology feasibility.
Ethics: This project does not involve ethical aspects.
Workplace location: Campus Sescelades, Tarragona
37.5 hours a week
15 March 2021
|This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 945413|